fix: improve explicit browser profile selection across CLI and DSH

[iuyo5678]

Refs #219.

When a task requires Chrome profile A but only profile B is connected, an unqualified session start selects B. The existing browser selector can select A correctly once its extension instance is known, but users and agents lacked a consistent way to establish and carry that mapping across the CLI and DeepSeek Harness.

This PR provides a partial mitigation through an explicit profile-selection workflow. It does not fully implement #219's requested profile discovery and enforced task/workspace binding, so the issue should remain open.

Changes

• Add Copy profile instructions to the extension popup. It copies both the exact CLI command and the native DSH browser_session call for the current instance, with guidance to use the appropriate interface for every new session. DSH users are directed to use the tool instead of starting a separate CLI session. Copying is disabled when disconnected or before the instance ID is available; clipboard failures do not report success. English, Chinese, and Korean are covered.
• Require a verified profile-to-instance mapping in both the CLI skill and the independent DSH skill, even with only one connected browser. Unknown mappings require user confirmation; unavailable targets require reconnection, without dropping or replacing the selector.
• Correct the public DSH session-tool description and share its browser-parameter guidance with the internal action schema. Remove the misleading claim that a selector is needed only when multiple browsers are connected. Ordinary tasks without a required profile keep the optional parameter and existing routing behavior.
• Document how to verify Profile Path through chrome://version, use the same profile's popup ID, and select it through either interface. Explain Windows/macOS behavior and why Chrome process arguments cannot prove which profile owns an extension instance.

Scope and remaining limitations

This uses the existing instance-ID/unique-label routing; it adds no browser permissions, filesystem scanning, automatic profile metadata, or persisted required-profile configuration. An explicitly supplied unavailable or ambiguous selector is rejected. A requirement expressed only in conversation is not enforced by the program if the agent omits the selector: with just B connected, an unqualified start can still select B. This remaining case was reproduced in the validation, not treated as fixed.

Instance IDs are routing identifiers, not independent proof of a filesystem path. Users must confirm the initial mapping, and reconfirm it after extension storage resets or profile cloning.

Validation

Final follow-up commit: 88718fd, on the existing PR base c6c888e.

• 29 live checks passed on Windows 11 with Chrome for Testing 153.0.8010.36, two disposable profiles under one User Data root, the built extension/CLI/daemon, and a local page containing different per-profile storage markers. The DSH checks invoke the actual registered tools and real process runner, rather than mock CLI responses.
• Clicked the popup copy buttons using browser input and the real clipboard API. Checked both copied interfaces carry the same instance ID. The CLI command and DSH call select A and read marker A while B remains connected; selecting B reads marker B.
• With A disconnected and B connected, explicit A selection returns not_found. The DSH call sends one selected start, performs no navigation, creates no owned session, and does not retry on B. Reconnecting A restores the same selector.
• Verified unique-label selection and duplicate-label rejection (invalid_params) through DSH, with no fallback. Confirmed ordinary unqualified starts still select the sole online browser, including B when A is offline. All validation sessions, browser processes, and the isolated daemon were stopped.
• pnpm lint: passed, including DSH typecheck and 333 tests. Five added DSH cases cover ID/label forwarding, failure propagation without fallback/navigation, and compatibility of unqualified starts.
• Popup/App tests: 34 passed, including the seven profile-copy cases now checking the exact DSH call as well as the CLI command, changed identity, clipboard failure/retry, unavailable targets, and translations.
• Localization tests: 52 passed. Extension TypeScript compilation, extension production build, and DSH production build passed.
• Earlier validation of the initial popup implementation: full extension suite 1,873 passed / 103 environment-gated skipped, Rust formatting and 18 browser-selector tests passed. No Rust changes were added in this follow-up.

The earlier additional Windows skill-install check had 34 passing tests and two Hermes path-layout failures (skills_dirs_match_harness_spec, detects_hermes_from_home_layout), both reproduced on unchanged main. Those unrelated files remain unchanged.

macOS shares the implementation and documented workflow; no macOS hardware test is claimed. These checks establish explicit-selector behavior, not that every model will always follow the guidance.