ci: run build entirely through Dagger; drop prek from CI

The Forgejo k8s job image is a thin Alpine + Dagger orchestrator (no native
Rust/Neovim toolchain, no prek) with a DinD sidecar — so CI was failing on
step 1 (`prek: command not found`) on every run, and a native cargo hook
wouldn't work there either.

- build.yaml now runs `dagger call check` (cargo fmt/clippy/test on
  rust:1-bookworm) + `dagger call test-nvim` (build hephd + headless e2e).
- New Dagger `check` function; CARGO_BUILD_JOBS capped on both functions so
  parallel rustc on heavy crates doesn't OOM the build engine; cargo registry
  + target caches shared across runs.
- prek is intentionally not run in CI — it runs locally via git hooks.

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

docs/reference/tech-spec.md

@@ -344,7 +344,7 @@ See [[design]] §5–§7 for the constraints later phases impose on present choi
 - ✅ **Hub auth — verification side (§13, slice 10a):** the hub validates an **OIDC bearer token** (`jsonwebtoken`, RS256-pinned, exact iss+aud, exp/nbf, required `sub`; JWKS discovered + cached, refetched on unknown `kid`) on `/sync/*` + `/rpc`. A [`TokenVerifier`] trait seam keeps it mockable; **single-tenant** owner gate (`authorize_owner_sub`: claim-on-first, then require-match → 403 for any other identity). `--oidc-issuer`/`--oidc-audience` enable it (open when unset, for local dev). Tested fully offline: stub-verifier middleware tests + an adversarial battery against an in-process mock IdP (expired/wrong-iss/wrong-aud/unknown-kid/tampered/alg-confusion/missing-sub all rejected).
 - ✅ **Auth — client side (§13, slice 10b):** OAuth2 **device-code flow** (`hephd::oauth::DeviceFlow`: discover → start → poll handling `authorization_pending`/`slow_down`, + refresh). `TokenStore` (OS keyring via `keyring`, in-memory for tests); `current_bearer` refreshes on expiry. `heph auth login` runs the flow + caches the token; spokes (`sync_once`) and `client` mode (`RemoteStore`) attach the bearer, refreshing as needed (`--oidc-issuer`/`--oidc-client-id`). **All auth/proxy HTTP uses `ureq`** (runtime-free blocking) — `reqwest::blocking` panics inside the daemon's `spawn_blocking`; async `reqwest` remains only for `sync_once`. Tested offline against a mock OAuth server (device flow, refresh, store) + a full spoke⇄authed-hub loop.
 - ✅ **CLI (§1):** `heph` next/task/doc/get/export/search/journal/**auth login·logout**.
-- ✅ **CI (§9):** `.forgejo/scripts/build` runs fmt/clippy/test (self-bootstrapping rustup).
+- ✅ **CI (§9):** Forgejo `build.yaml` runs **entirely through Dagger** (the k8s job image is a thin Alpine + Dagger orchestrator with a DinD sidecar — no native Rust/nvim toolchain): `dagger call check` (cargo fmt/clippy/test on `rust:1-bookworm`) + `dagger call test-nvim` (build hephd + headless e2e). Cargo parallelism capped (`CARGO_BUILD_JOBS`) to avoid OOMing the build engine; cargo caches shared across runs. `prek` runs locally via git hooks, not in CI.
 - ✅ **`heph.nvim` slice 11a (§8) — the primary surface begins:** the Lua plugin (`heph.nvim/`) as a thin client of the `hephd` unix socket. **RPC client** over a `vim.uv` pipe (blocking `call` via `vim.wait`; id-demuxed; partial-line buffered; `luanil` so JSON `null`→`nil`; isolated `Session`s for tests). **Buffer-backed nodes** — `heph://node/<id>` buffers (`buftype=acwrite`), `BufReadCmd`→`node.get` / `BufWriteCmd`→`node.update` (whole-buffer body, CRDT-diffed; exact round-trip). **`[[wiki-link]]` follow** on `<CR>` via a new **`node.resolve {title}`** RPC (exact alias-then-title match, the same mapping that materializes `wiki` links — never fuzzy `search`; unresolved links allowed). **Daily journal** (`:Heph today`/`journal <date>`, idempotent). `:Heph` command surface + completion. **Headless e2e (§9):** drives the plugin in `nvim --headless` against a real daemon over a temp socket via a **self-contained busted-style runner** (`tests/e2e/runner.lua` — no external plugins/network, deterministic exit codes); specs cover journal round-trip, follow-link (+ unresolved no-op), and link-two-docs/backlink. `mise run test-nvim` builds the daemon and runs the suite (dev: system nvim/rustc; CI: a Dagger container provides them — slice 11c).
 - ✅ **`heph.nvim` slice 11b (§8) — task views:** **`list` enriched** to titled [`RankedTask`] rows (title + `canonical_context_id`, shared `ranked_from_row` with `next`) so the Organizational view needs no N+1 `node.get`. Plugin: **Tactical `next`** + **Organizational `list`** views (rendered scratch buffers, `<CR>` opens a row's canonical-context doc — the node autocmd narrowed to `heph://node/*` so view buffers don't trip it); **task capture**, **set-attention**, **done/drop**, **skip**, **per-task `log` append** — all resolving "the current task" from the buffer (a `task` node, or a context doc via its `canonical-context` backlink); **`vim.ui.select` picker** (`picker.lua`) with Telescope auto-upgrade; `:Heph next/list/capture/attention/done/drop/skip/log/search` subcommands. e2e specs: **capture→next→open context→add/check checklist→done**, and **recurring fresh-checklist** (complete rolls forward in place; the next occurrence is all-unchecked — the §4.4 hard requirement).
 - ✅ **`heph.nvim` slice 11c (§8) — promotion + Dagger CI:** backend **`task.promote {container_id, item_ref, attention?, project?}`** — mints a committed task from the `item_ref`-th `- [ ]` context item (1-based, document order via a new `extract::context_item_lines`) and rewrites that source line into a `[[link]]` to it. **Wiki-link resolution now excludes canonical-context docs** (`resolve_id`), so `[[Task Title]]` deterministically resolves to the task, not its identically-titled context doc — a general fix surfaced by promotion. Plugin: `:Heph promote`, `promote_under_cursor` (save-if-dirty → `util.context_item_index_at_cursor` mirrors extract's fence rules → `task.promote` → reload). e2e spec (f). **CI via Dagger:** a `test_nvim` function in `.dagger/` bakes a **pinned, arch-detected Neovim** (`v0.11.2`; Debian's is too old for `vim.uv`) onto `rust:1-bookworm`, builds `hephd`, and runs the shim suite (cargo + cargo-target cache volumes); `build.yaml` calls `dagger call test-nvim`. `run.lua` fails on zero-specs (no false-green) — validated end-to-end (failing spec → Dagger exit 1).