[ponytail] Web server: delete dead SSE subsystem, route map, graph-queries dedupe #122

Cut

Server-side half of the visualizer: routing, data queries and the dead SSE subsystem.

Findings

• delete: the whole SSE subsystem. No page opens an EventSource; all four views poll /api/diff every 1.5 s (verified with rg EventSource across the repo: only a comment in auth-gate.ts, the unit test and a phase-4 plan doc). Drop src/interfaces/web/routes/sse.ts, handleGraphEvents, the two /api/events routes, getSseClientCount and the broadcastUpdate(db) call in the WAL watcher; keep the watcher for its two cache resets (~75 lines). Update the "Real-time SSE updates" lines in CLAUDE.md and README.md.
• stdlib: the 138-line if (pathname === ... || pathname === ...) chain plus seven one-line handler modules that all do writeHead(200, JSON_HEADERS); end(JSON.stringify(fn(db))) (src/interfaces/web/server.ts:118, routes/graph.ts:17, routes/words.ts:9). A Map<string, (db, url) => unknown> for JSON routes and a Map<string, string> for pre-rendered pages with one generic responder (~100 lines).
• delete: route aliases nothing requests: /api/diff, /depth/api/diff, /depth/api/threshold, /api/dream/status, /api/dream/start, /api/words, /words/api/words, /graph/api/health (verified by rg over every fetch(, Invoke-* and curl in the repo). Keep the prefixes the templates call plus /api/health for the supervisor probe (~14 lines). Re-verify scripts/*.ps1 and scripts/*.sh health probes before removing any /health alias.
• shrink: getGraphData is getDepthGraphData minus lastActive / bridgeScore (src/interfaces/web/data/graph-queries.ts:69). Serve the depth payload everywhere; consumers ignore extra fields and terminal/graph.html.ts already reads the two fields it never receives (~50 lines).
• shrink: getGraphDiff runs the same six-column SELECT twice with a different predicate (graph-queries.ts:215, ~20 lines).
• shrink: computeOptimalThreshold's fallback re-runs both count queries (graph-queries.ts:190, ~16 lines).
• delete: isDreamRunning (src/interfaces/web/routes/dream.ts:33), zero importers.
• yagni: src/interfaces/web/paths.ts (returns loadConfig().dbPath), src/interfaces/web/bind.ts (two-key env lookup) and resolveDreamLogPath in routes/dream.ts:23 (identical to src/dream/daemon.ts:50, with a contract test asserting the copies agree). Inline the first two, import the daemon's function for the third and delete that contract test (~40 lines).

Verification

npm run build and npm run test:run green before and after. Start the server on a spare port with the real database read-only and curl every route the four page templates and the terminal pages call; every one returns the same status and JSON shape as before (capture before, diff after).