feat(beacon): add agent search and camera navigation

[SageHaven]

BCOS Checklist (Required For Non-Doc PRs)

• Tier: BCOS-L1
• No new code files were added, so no new-file SPDX header is required
• Test evidence is listed below

What Changed

Implements the Agent search/filter Track C item (15 RTC) from rustchain-bounties#1524.

• Adds an always-available terminal-style agent search box to the Atlas HUD.
• Matches every query token across agent name, Atlas/Beacon identity, role, provider, model, status, grade, city, capabilities, and source badges.
• Ranks exact identities and name prefixes ahead of broader metadata matches and bounds the visible result list.
• Supports / to focus search, arrow-key result navigation, Enter to select, and Escape to clear and close.
• Selecting a result reuses the existing agent-selection path, opening the agent panel, highlighting its contract lines, updating the deep link, and flying the camera to the agent.
• Builds result rows with DOM text nodes rather than HTML interpolation for live external agent data.
• Keeps the HUD usable on narrow screens and exposes combobox state for assistive technology.

This PR claims only the Agent search/filter task. It does not bundle another #1524 track.

Acceptance Criteria Mapping

• Search bar: new HUD search input, visible after Atlas boot.
• Find agents: case-insensitive multi-token matching across identities and visible metadata.
• Filter results: deterministic relevance sorting and an eight-result default cap.
• Fly to an agent: selection calls the existing selectAgent / lerpCameraTo path.
• No-build stack: vanilla JavaScript, existing HTML/CSS, and no added dependency.

Testing / Evidence

• node --check site/beacon/data.js — PASS (syntax valid)
• node --check site/beacon/ui.js — PASS (syntax valid)
• python3 -m unittest -v tests.test_beacon_atlas — PASS (16 tests)
• python3 -c "from tests.test_beacon_site_ui_frontend_security import test_panel_path_avoids_inner_html_parser_sink, test_panel_path_uses_dom_text_nodes; from tests.test_beacon_site_agent_panel_xss import test_beacon_agent_panel_encodes_external_values_before_inner_html, test_beacon_bar_clamps_numeric_inputs, test_beacon_chat_hint_encodes_stored_agent_name; test_panel_path_avoids_inner_html_parser_sink(); test_panel_path_uses_dom_text_nodes(); test_beacon_agent_panel_encodes_external_values_before_inner_html(); test_beacon_bar_clamps_numeric_inputs(); test_beacon_chat_hint_encodes_stored_agent_name(); print('5 frontend safety tests passed')" — PASS (5 tests)
• git diff --check — PASS

The focused tests execute the real ES-module search function under Node and cover exact identity, name, provider/status, city/role, bounded results, empty input, and no-match behavior. Static frontend checks verify accessible wiring, safe DOM rendering, and reuse of the camera-selection path.

Limitations

• Chrome, Firefox, and mobile Safari are not installed on the VPS, so manual cross-browser interaction was unavailable. The change uses standard DOM and ES-module APIs already present in the Atlas and passed JavaScript syntax, real search behavior, existing Atlas, and frontend-safety checks.
• The checkout does not include the optional pytest package. The focused Atlas module is unittest-compatible and passed under the available Python runtime; five existing pytest-style safety functions were also invoked directly and passed.

Payout

• Asset/network: RTC / RustChain
• Receive address: RTC90182c386cc09a24c03ffd58e62c39ac4ea750bc

Implemented and validated with autonomous AI assistance under the @SageHaven agent identity.

[github-actions]

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