fix(cli): repair search and status commands

[Batchputz]

Summary

pi-session-cli cannot run two of its commands against the current server (reproduced on the v0.8.6 release binaries and on main = a09ae455, which is the same commit the tag points at):

command	result
pi-session-cli search <query>	Command failed: 命令 'search_sessions_fts' 失败: Failed to prepare FTS5 statement: no such table: sessions_fts
pi-session-cli status	Command failed: 服务端返回了非 JSON 响应 (http://localhost:52131/health) — 可能服务端版本不匹配

Two independent causes, one commit each.

1. search — the legacy sessions_fts table is gone

src-tauri-cli/src/run.rs calls the app command search_sessions_fts, which resolves to data/sqlite/legacy_fts.rs::search_fts5():

SELECT path FROM sessions_fts WHERE sessions_fts MATCH ?

Since message-level FTS became the primary search path, data/sqlite/bootstrap.rs only builds ensure_message_fts_schema() and notes "Legacy session-level FTS remains disabled regardless of config"; init_fts5() — the only caller of full_rebuild_fts() — has no callers left, so sessions_fts is never created and the command always fails.

This is the bug reported in #62. That issue is closed as "Fixed by 208190a4: CLI session search now uses the current message_fts index instead of the removed sessions_fts table", but that commit does not exist in this repository, and the failure still reproduces on main/v0.8.6:

$ gh api repos/Dwsy/pi-session-manager/commits/208190a4
gh: No commit found for SHA: 208190a4 (HTTP 422)

$ gh api repos/Dwsy/pi-session-manager/commits/main --jq '.sha'
a09ae455595e90c79776f4f8821aee5cb54c8d2b
$ gh api repos/Dwsy/pi-session-manager/git/ref/tags/v0.8.6 --jq '.object.sha'
a09ae455595e90c79776f4f8821aee5cb54c8d2b   # tag == main

$ gh api "repos/Dwsy/pi-session-manager/contents/src-tauri-cli/src/run.rs?ref=main" \
    --jq '.content' | base64 -d | sed -n '490p'
            let data = request_command(&client, &base_url, "search_sessions_fts", json!({ "query": query })).await?;

This PR does what that closing comment describes — the CLI now uses the current message_fts index, via the existing full_text_search command (same one the UI's search uses):

request_command(&client, &base_url, "full_text_search",
    json!({ "query": query, "role_filter": "all", "page": 0, "page_size": 20 }))

Result: scored message hits with content snippets, session_path and timestamps (previously the command returned up to 50 SessionInfo rows; message-level hits are what the maintained index can serve).

2. status — there is no /health route to probe

request_status() requests GET {base_url}/health. The router in src/server/http/mod.rs registers /api, /api/events, /v1/*, /ws and /metrics — no /health, so the request falls through to the embedded-SPA handler, which answers with index.html, and resp.json() fails on the HTML.

The fix keeps /health as the first probe (for deployments that do expose it) and falls back to /v1/observability/summary, which is served in desktop and headless mode and reports exactly what status is for:

$ pi-session-cli status
{
  "data": {
    "capabilities": { "analytics_overview": true, "memory_recall": true, ... },
    "endpoints": [ "/v1/sessions", "/v1/memory/recall", ... ]

Testing

Built with cargo build --release -p pi-session-cli (feature cli, no Tauri/WebKit needed) and run against a running 0.8.6 desktop app with a schema-v19 database (~/.pi/agent/sessions/sessions.db), which is the environment from #62:

# before (stock 0.8.6 release binary)
$ pi-session-cli search waybar
ERROR 命令 'search_sessions_fts' 失败: Failed to prepare FTS5 statement: no such table: sessions_fts
$ pi-session-cli status
ERROR 服务端返回了非 JSON 响应 (http://localhost:52131/health) — 可能服务端版本不匹配

# after
$ pi-session-cli search waybar
{
  "has_more": true,
  "hits": [
    {
      "content": "restart waybar",
      "entry_id": "63b4db64",
      "match_reason": "content",
      "role": "user",
      "score": 14.397594451904297,
      "session_id": "019f6366-2abc-70bf-886c-5fd1640bf41a",
      "session_path": "/home/user/.pi/agent/sessions/---/2026-07-15T01-31-07-836Z_019f6366-....jsonl",
      "source_type": "user",
      "timestamp": "2026-07-15T02:47:55.604Z"
    },
    ...
  ]
}
$ pi-session-cli status
{ "data": { "capabilities": { "analytics_overview": true, ... } } }

session list, session get, tag, model etc. are untouched and still work.

Alternatives considered

• Make the server-side search_sessions_fts fall back to the message index, so existing CLI builds keep working too. That changes the command's return shape (Vec<SessionInfo> → hits), so it is a behavioural change on a public command — happy to implement it instead if you prefer that direction.
• Add a /health route server-side rather than adjusting the client. Also fine by me if you would rather have the conventional endpoint.

Both commits are independent — happy to split them into separate PRs if that is easier to review.