feat(cli): complete task surface — human dates, recurrence, full API

Make heph a real task driver and the complete daemon-API surface (the
three-surface model's capture/scripting role). Structured fields are flags.

- datespec: human date parsing (today/tomorrow/+3d/fri/ISO, injectable today
  for deterministic tests) + compact display; recurrence presets + the common
  Todoist-style natural-language forms ("every 3 days", "every fri", "every
  April 15") + raw RRULE passthrough. Table-driven unit tests.
- main: new commands covering every RPC — list, done/drop/skip, attention,
  edit (reschedule via task.set_schedule), promote, show, log (append/tail),
  health, node update/rm, resolve, links/backlinks, link add,
  project add [--parent], sync [--status], conflicts [resolve]. task/next/list
  show human dates; projects referenced by name (resolved, errors if absent).
- tests/cli.rs: real-socket process tests for the new verbs.

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

docs/changelog.d/v1-prototype.feature.md

@@ -20,3 +20,4 @@ Begin the v1 prototype (Phase 1, tech-spec §11.1), built in TDD slices:
 - `heph.nvim` managed daemon — plug-and-play by default: `require("heph").setup({})` spawns and supervises a local `hephd` against the default paths when none is running, kills only the daemon it spawned on exit, and self-heals (respawns + reconnects if the daemon dies mid-session). A daemon you started yourself (a `server`/`client` architecture, or a service) is always respected — the plugin only spawns when nothing is serving the socket; with `autostart = false` it connects only and warns if unreachable. `$HEPH_SOCKET` / `$HEPH_DB` isolate a development Neovim onto a separate daemon + DB.
 - `heph.nvim` follow-or-create: pressing `<CR>` on a `[[wiki-link]]` whose target doesn't exist yet now **creates** a doc with that title and opens it (the zettelkasten gesture), materializing the source's backlink — so you can link a journal entry to a brand-new note in one keystroke. Plus `:Heph doc <title>` to create a standalone wiki entry, and `:Heph home` — a single designated landing/index page (open-or-create by title, configurable via `opts.home`) to grow a map of content around. `:Heph journals` opens a recent-days picker (preview existing days, `@create` for new ones; count via `opts.journal_days`, default 7) — the dailies workflow. Pickers (Telescope) now support a preview pane. The `:Heph next`/`list` views are interactive: `<CR>` opens a task's context, `a` adds a task (prompt title + attention), `d` marks the task under the cursor done, `r` refreshes — with a dimmed key hint shown above the list.
 - Dev/installed isolation tooling: a `mise run dev` task runs the working-tree `hephd` on isolated `.dev/` paths, and a how-to ([[install-heph]]) covers installing `heph`/`hephd` from the forge (build-from-source), the lazy.nvim plugin setup, and pointing a dev Neovim at the dev daemon via `$HEPH_SOCKET`/`$HEPH_DB` so it never touches the installed store.
+- CLI as a complete task surface (§1, §6.2.1): `heph` now implements the entire daemon API and is the task capture/scripting surface. Structured fields are flags with **human dates** (`--do-date tomorrow|+3d|fri|YYYY-MM-DD`, shown back compactly in `next`/`list`) and **recurrence** (`--recur` presets/natural-language like "every 3 days", or a raw `--rrule`). New verbs: `list`, `done`/`drop`/`skip`, `attention`, `edit` (reschedule do-date/late-on/recurrence, re-attention, re-file — backed by the new `task.set_schedule` RPC), `promote`, `show`, `log` (append or tail), `health`, `node update`/`rm`, `resolve`, `links`/`backlinks`, `link add`, `project add [--parent]`, `sync [--status]`, `conflicts [resolve]`. Projects are referenced by name. Date/recurrence parsing is unit-tested; the new verbs have real-socket process tests.