feat(lanes): lane runtime UI, docs, and env additions (A1+A2)

Client-side rendering for the per-lane runtime facts (slot, ports,
database, Redis index, service liveness) added in the server-side
A1/A2 work, plus the doc updates (README, CLAUDE.md, docs/API.md,
client/server READMEs) describing the new profile.env keys, hook
environment contract, and REST endpoints.

README.md

@@ -80,8 +80,25 @@ events and expires after `DETECTION_TTL_MS` (default 5 minutes), so a lane can
 move backwards between work sessions. Detection never writes the declared stage,
 and an inferred node never renders as done.
 
+A lane can also run **its own application stack**, isolated per lane, when its
+repository declares a profile at `<repo>/.ccam/profile/` — a `profile.env` of
+declarations plus shell hooks the dashboard calls. Each lane gets a slot, and its
+ports and per-lane directories derive from it:
+
+```bash
+ccam lanes up          # boot the stack of the lane owning this directory
+ccam lanes runtime     # slot, ports, service health
+ccam lanes logs api    # tail a service log
+ccam lanes down
+```
+
+Services are fully detached, so restarting the dashboard never stops a running
+lane. This is resource namespacing on the host, not a container: lanes run as the
+same user and share the network.
+
 [`docs/LANES.md`](docs/LANES.md) has the pipeline model, the destroy guard, the
-preflight contract, the Workspace page, and `GET /api/lanes/:id/git`.
+preflight contract, the Workspace page, `GET /api/lanes/:id/git`, and the full
+runtime/profile contract.
 
 ## Tests