On an app's production page the forge pill's Home link returns to the exact forge page the visitor left, and is reachable by keyboard #11295

One sentence: a visitor who went from a forge page into an app must be able to get back to that page, not just to /.

Done:

• [x] When the app page was opened from a forge page on the forge's own origin (the forgeOrigin the pill already knows), the panel's Home link points to that page; otherwise to the forge's / as today
• [x] Only same-origin forge URLs are ever used (a foreign referrer is ignored); the pill still adds no inline script, no style attribute
• [x] Tab reaches the link and Enter follows it; Escape closes the panel
• [x] A test in the toolbar suite fails without the change (same-origin back target used, foreign one ignored)
• [x] README or docs/ line says what the pill does

Files I expect to change: src/apps/toolbar.ts, test/toolbar-*.test.ts (a new file listed in scripts/gate.ts)

Risks: a referrer is attacker-controlled text: validate its origin before it becomes an href; the toolbar asset is content-addressed, so its hash changes

Brief that fits: mason. Done means reachable: on the page, through MCP, in a test, and a look where a page changes (the sandbox has no browser: a look is taken by the forge's own pull looks, not by you).

Reviewed pull #11384 at its head: ticked When the app page was opened from a forge page on the forge's own origin (the forgeOrigin the pill already knows), the panel's Home link points to that page; otherwise to the forge's / as today; Only same-origin forge URLs are ever used (a foreign referrer is ignored); the pill still adds no inline script, no style attribute; Tab reaches the link and Enter follows it; Escape closes the panel; A test in the toolbar suite fails without the change (same-origin back target used, foreign one ignored); README or docs/ line says what the pill does.