heph.nvim: task views — next/list/capture/attention/state/log (slice 11b)

Backend: enrich `list` to return titled RankedTask rows (title +
canonical_context_id, via a shared ranked_from_row with `next`), so the
Organizational view needs no N+1 node.get. TDD: query_surface test asserts
list rows carry title + context id.

Plugin:
- view.lua: Tactical `next` + Organizational `list` rendered scratch buffers;
  <CR> opens the row's canonical-context doc. Narrowed the node autocmd to
  heph://node/* so view buffers (heph://next, heph://list) don't trip it.
- task.lua: 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).
- picker.lua: vim.ui.select with Telescope auto-upgrade (headless-safe).
- command.lua: :Heph next/list/capture/attention/done/drop/skip/log/search.

e2e: capture→next→open context→add/check checklist→done; recurring
fresh-checklist (complete rolls forward in place, next occurrence all-unchecked
— the §4.4 hard requirement). 6 specs green via `mise run test-nvim`.

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

heph.nvim/lua/heph/task.lua

@@ -0,0 +1,90 @@
+--- Task actions (tech-spec §8): capture, attention, state, skip, log. Actions
+--- that operate on "the current task" resolve it from the buffer — either the
+--- buffer is a `task` node, or it is a task's canonical-context doc, in which
+--- case we follow the `canonical-context` backlink to its owning task.
+
+local rpc = require("heph.rpc")
+local util = require("heph.util")
+
+local M = {}
+
+--- Capture a committed task. `opts`: attention, do_date, late_on, recurrence,
+--- project. Returns the created task.
+function M.capture(title, opts)
+  opts = opts or {}
+  return rpc.call("task.create", {
+    title = title,
+    attention = opts.attention,
+    do_date = opts.do_date,
+    late_on = opts.late_on,
+    recurrence = opts.recurrence,
+    project_id = opts.project,
+  })
+end
+
+--- The committed task id associated with the current buffer, or nil.
+function M.current_task_id()
+  local buf = vim.api.nvim_get_current_buf()
+  local id = vim.b[buf].heph_node_id
+  if not id then
+    return nil
+  end
+  if vim.b[buf].heph_node_kind == "task" then
+    return id
+  end
+  -- A canonical-context doc: its owning task is the src of the
+  -- canonical-context link pointing here.
+  for _, l in ipairs(rpc.call("links.backlinks", { id = id })) do
+    if l.link_type == "canonical-context" then
+      return l.src_id
+    end
+  end
+  return nil
+end
+
+local function with_task(action, what)
+  local id = M.current_task_id()
+  if not id then
+    util.notify("no task associated with this buffer", vim.log.levels.WARN)
+    return nil
+  end
+  action(id)
+  if what then
+    util.notify(what)
+  end
+  return id
+end
+
+--- Mark the current task done/dropped (recurring tasks roll forward on done).
+function M.set_state_current(state)
+  return with_task(function(id)
+    rpc.call("task.set_state", { id = id, state = state })
+  end, "task " .. state)
+end
+
+--- Set the current task's attention.
+function M.set_attention_current(attention)
+  return with_task(function(id)
+    rpc.call("task.set_attention", { id = id, attention = attention })
+  end, "attention → " .. attention)
+end
+
+--- Skip the current recurring task's occurrence (advance without logging).
+function M.skip_current()
+  return with_task(function(id)
+    rpc.call("task.skip", { id = id })
+  end, "occurrence skipped")
+end
+
+--- Append a line to the current task's log (the resumption breadcrumb).
+function M.log_append_current(text)
+  if not text or #text == 0 then
+    util.notify("nothing to log", vim.log.levels.WARN)
+    return nil
+  end
+  return with_task(function(id)
+    rpc.call("log.append", { task_id = id, text = text })
+  end, "logged")
+end
+
+return M