fix(observability): stamp page URL on screenshot/network; enable capture on --clear (issue #8)

Field report #8: in extension-relay sessions, reads (eval/screenshot/network)
could silently run against whatever tab drifted into focus, with no signal,
and network capture was intermittently empty.

- #8.1: screenshot and `network requests` now print `screenshot @ <url>` /
  `network @ <url>` to stderr (mirrors the existing `eval @ <url>`), and the
  responses carry `origin`. A read against the wrong/drifted tab — and the
  "0 captured" vs "wrong page" ambiguity — is now obvious.
- #8.3: `network requests --clear` now enables Network capture immediately
  instead of lazily on the next read, so requests fired between `--clear` and
  the following read are tracked (fixes the "No requests captured" on first
  try, works on retry" race). Extracted enable_request_tracking helper.
- #8.2: the daemon version-mismatch restart notice now spells out that
  in-memory context (active tab, refs, captured requests) is reset and tells
  the user to re-open the target URL if the next read looks blank/wrong.

Verified on a launched browser: coordinate clicks land, screenshot/network
stamps appear, and a fetch after --clear is captured on the first read.

cli/src/connection.rs

@@ -625,7 +625,10 @@ pub fn ensure_daemon(session: &str, opts: &DaemonOptions) -> Result<DaemonResult
             // version (e.g. after an upgrade), kill it and start a fresh one.
             if !daemon_version_matches(session) {
                 eprintln!(
-                    "{} Daemon version mismatch detected, restarting...",
+                    "{} Daemon version mismatch detected, restarting... \
+                     In-memory context (active tab, refs, captured requests) is reset. \
+                     If the next read looks blank or lands on the wrong page, re-open \
+                     your target URL before retrying (issue #8.2).",
                     crate::color::warning_indicator()
                 );
                 // Best-effort: ask the old daemon for its current URL so the