Implements `docs/journey-stage1b2-lsp-guidance-framing.md` (approved at
revision 4, after three review rounds). Lua, tests and docs; no Rust
change and no protocol change.
`COHERENCE.md` §1.2's canonical silence: a preconfigured server that is
not installed failed with no status message, no record and no modeline
marker, while tree-sitter highlighting kept working and masked it. Now
the status line names the command, the language and the errno; the
modeline reads `LSP:!` instead of nothing; and `M-x lsp.status` renders
a durable `*lsp*` panel.
Half of this was already built. `status_buffer_text()` and
`last_error()` have existed since M4.8, exposed to Lua and tested, with
no production caller and no buffer to render into — several doc
comments already referred to "the `*lsp*` buffer" as though it existed.
The reporting shape was likewise already adopted twice inside
`lsp.lua`; the canonical case was silent because nobody had converted
it.
Three tables with three lifetimes, because one cannot do the job:
`reported` is never cleared and includes the command, so repointing at
another missing executable reports again; `failures` is cleared by a
successful spawn so the panel goes quiet on recovery; and a
buffer-keyed projection feeds the modeline, because that provider runs
for every window on every paint and deriving an affinity key inside it
would invoke root resolvers during painting.
The memo is on the report, not the failure: the spawn is still
attempted on every file open, so installing the binary mid-session
recovers with nothing to invalidate.
Adds `tests/lsp_spawn_guidance_acceptance.rs` (16 pins) and a step-6
row to the journey ratchet.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lv428Fth9LRtffwJSsqH7T