feat: wiki-links by id — id-first resolution + heph.nvim [[ picker (§8.4)

Backend: `links::resolve_id` now checks for an exact live node id before
alias/title, so a canonical `[[NODEID]]` link resolves to its node and
can't be shadowed by a like-named node. Legacy `[[Name]]` links still
resolve by name (until the migration), so this is additive.

heph.nvim: `link.insert` (bound to insert-mode `[[` and `:Heph link`)
searches via the `search` RPC and inserts `[[NODEID]]`, with a "+ Create
new doc" entry; `<CR>` follow resolves the id directly. e2e covers
search→insert→materialize and the create path.

Remaining (§8.4): read-expansion/conceal display + the one-time
[[Title]]→[[NODEID]] migration (then retire name-resolution + the hack).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/reference/tech-spec.md

@@ -329,15 +329,16 @@ Field rules: `id`/`kind` are **read-only** (display only); `title`, `attention`,
 
 **Inline `#hashtags`** are a **`heph.nvim` feature**, not core extraction (for now): the plugin detects them on save and routes them through the same `tag.add`/`tag.remove` path. (Core-side hashtag extraction can come later, e.g. for the zk import.)
 
-## 8.4 Wiki-links by node id (planned)
+## 8.4 Wiki-links by node id (authoring built; display + migration next)
 
-> **Status: planned** (§14 roadmap, 2026-06-03). Today bodies store the human text `[[Title]]` and links are materialized by resolving name→id at write time, which is ambiguous (a task and its canonical-context doc share a title — hence the resolution hack in §6/`links::resolve_id`). The fix: **the body stores the canonical node id**, and **no name-addressed link ever enters the DB**.
+> **Status: id-addressed links + the `[[` picker are built**; read-expansion/conceal display and the legacy migration are next. Historically bodies stored the human text `[[Title]]` and links materialized by resolving name→id at write time, which is ambiguous (a task and its canonical-context doc share a title — hence the resolution hack in §6/`links::resolve_id`). The fix: **the body stores the canonical node id**, and **no name-addressed link ever enters the DB**.
 
-- **At rest:** `[[NODEID]]`, or `[[NODEID|custom text]]` when the author wrote explicit display text. Extraction reads the id directly — no resolution, no ambiguity — and the canonical-context exclusion hack in `resolve_id` is **removed**.
-- **Projection (same philosophy as §8.3):** on **read**, `heph-core` expands a bare `[[NODEID]]` → `[[NODEID|Current Name]]`, so buffers, `heph export`, and any dumb reader show readable, always-fresh link text. On **write**, a `|text` that equals the target's current name **collapses back** to bare `[[NODEID]]`; a `|text` that differs is preserved as a real override. Needs an **id→name batch resolve** RPC for the expansion.
-- **`heph.nvim` authoring:** typing `[[` triggers a picker (reuse `picker.lua` / Telescope, **no new dependency**) that searches titles via the `search` RPC and inserts `[[NODEID]]`; a **"Create new: «typed»"** entry mints a `doc` and inserts its id.
-- **`heph.nvim` display:** a completed link is **concealed** to its name (or `|text`), rendered as a styled hyperlink (extmark `conceal` + inline virtual text), and revealed in raw form when the cursor is on it.
-- **Migration:** a **one-time fixup script** rewrites existing `[[Title]]` bodies to `[[NODEID]]` (resolve→id; flag the unresolvable). No special care is warranted — there is no critical data in the store yet — and a first-class migrations feature stays **deferred**.
+- ✅ **Resolution is id-first:** `links::resolve_id` checks for an exact live node **id** before alias/title, so `[[NODEID]]` resolves to its node (and a like-named node can't shadow it). Legacy `[[Name]]` links still resolve by name until the migration runs; the canonical-context exclusion hack therefore stays for now (removed once name-resolution is retired).
+- ✅ **`heph.nvim` authoring:** typing `[[` (or `:Heph link`) opens a picker (reuses `picker.lua` / Telescope, **no new dependency**) that searches via the `search` RPC and inserts `[[NODEID]]`; a **"+ Create new doc"** entry mints a `doc` and inserts its id. Follow (`<CR>`) resolves the id directly.
+- **At rest (target):** `[[NODEID]]`, or `[[NODEID|custom text]]` when the author wrote explicit display text. The id before the `|` is the target.
+- ⏳ **Projection (same philosophy as §8.3):** on **read**, expand a bare `[[NODEID]]` → `[[NODEID|Current Name]]` so buffers, `heph export`, and any dumb reader show readable, always-fresh link text; on **write**, a `|text` equal to the target's current name **collapses back** to bare. Needs an **id→name batch resolve** RPC.
+- ⏳ **`heph.nvim` display:** a completed link is **concealed** to its name (or `|text`), rendered as a styled hyperlink (extmark `conceal` + inline virtual text), revealed in raw form when the cursor is on it.
+- ⏳ **Migration:** a **one-time fixup** rewrites existing `[[Title]]` bodies to `[[NODEID]]` (resolve→id; flag the unresolvable), after which name-resolution + the canonical-context hack are removed. No special care is warranted (no critical data yet); a first-class migrations feature stays **deferred**.
 
 ## 9. Testing strategy (TDD, layered)
 
@@ -469,7 +470,7 @@ See [[design]] §5–§7 for the constraints later phases impose on present choi
    - ✅ **nvim task-navigation polish (§8) — DONE:** `:Heph next`/`list` rows now carry a compact **do/late date chip** (and a recurrence `↻`); `<CR>` already jumps to a row's canonical-context doc (read/navigate, not field-edit).
 3. ✅ **Tags (§4, §8.3) — DONE:** a tag is a `tag`-kind node whose id is **deterministic in `(owner, name)`** (`tag:<owner>:<name>`, like the journal), so a name is one canonical tag and replicas converge — no duplicate tag nodes. Tagging is an **OR-set `tagged` link** (mirroring `in-project`): `Store::add_tag` (get-or-create the tag node, idempotent link), `remove_tag` (tombstone the link), `tags_of` (sorted names); enumerate all tags via `list_nodes(Tag)`. RPCs `tag.add`/`tag.remove`/`tag.list` (+ RemoteStore forward); CLI `heph tag add|rm|list`. Names are trimmed, case preserved (canonical normalization deferred to the zk import). Unblocks the `tags:` line of the frontmatter surface (§8.3) and the eventual zk import; inline `#hashtags` remain a heph.nvim concern (§8.3).
 4. ✅ **YAML frontmatter as an edit surface (§8.3) — DONE:** the projection — `heph-core::frontmatter::strip` (conservative, runs in `update_node` before the CRDT diff) + `hephd::frontmatter::render` (local-tz dates via `datespec::fmt_iso`) behind `node.get {frontmatter: true}`; a task's context-doc surfaces the owning task's scalars + a `task:` ref; round-trip is a no-op and inbound frontmatter is always stripped (safe vs any client). And the `heph.nvim` smart client (`frontmatter.lua`): the buffer opens with the editable block, and `BufWriteCmd` diffs it → `title`→rename / `attention`→set_attention / dates→set_schedule / `project`→set_project / `tags`→tag.add·remove (a no-block buffer touches no metadata), and inline `#hashtags` in the body are unioned into the tag set on save.
-5. ⏳ **Wiki-links by node id (§8.4) — docs-first C1 (maybe C2):** canonical `[[NODEID]]` at rest, expanded/concealed for display; a `[[` picker; no name-links in the DB. Includes a one-time body fixup. See §8.4.
+5. ◐ **Wiki-links by node id (§8.4) — authoring DONE, display + migration next:** ✅ id-first resolution (`[[NODEID]]` resolves ahead of name; legacy `[[Name]]` still works) + the `heph.nvim` `[[` picker (`search` → insert `[[NODEID]]`, "+ Create" mints a doc) + id-direct follow. ⏳ Remaining: read-expansion/write-collapse projection (`[[ID]]`⟷`[[ID|Name]]`, needs an id→name batch RPC), conceal display, and the one-time `[[Title]]`→`[[ID]]` migration (then retire name-resolution + the canonical-context hack). See §8.4.
 6. ⏳ **`heph.nvim` slice 11d (§6/§8) — DEFERRED, post-parity:** daemon **server-push** notification framing (no-`id` lines on the socket; the client read-loop already demuxes them) + the **dirty-buffer reconcile** (the §8 "known-hard" case) + the "update-arrives-while-open" e2e (§9).
 7. ⏳ **Split `heph.nvim` to its own forge repo (§8) — UX polish:** generated from this monorepo (subtree-split in CI) so the lazy spec becomes `{ "eblume/heph.nvim" }` instead of a local-clone `dir` (see [[install-heph]]).
 8. ⏳ **Adoption refinement + multi-tenant (§13) — before v1 done, low priority:** local→authed **adoption** currently rewrites `owner_id` (`adopt_owner`) but not yet the owner-embedded deterministic ids (journal/tag) + their links; and the hub is single-tenant (one owner per store) — owner-per-token storage is a future extension.