fix(models): make unpriced guidance actionable

[avs-io]

Problem

The dashboard's unpriced-model warning is truncated in narrow terminals and its suggested command cannot be copied from the alternate-screen TUI. Users cannot reliably identify every affected raw model ID or run the remediation.

Root cause

The dashboard tried to fit model details and a fix hint inside a fixed-width panel. The plain models report had no dedicated unpriced filter, and applying normal --top or minimum-cost behavior before identifying unpriced rows could hide the rows users needed.

Change

• Add codeburn models --unpriced as a copyable plain-output path.
• Filter unpriced rows before applying --top, while preserving an explicit --min-cost threshold.
• Preserve exact raw model IDs in JSON and sanitize provider-supplied IDs in human-readable formats.
• Use deterministic, locale-independent ordering.
• Render the complete command at narrow dashboard widths, including real 42–44 column layouts.
• Document the new command.

This branch preserves the original contribution and authorship from #985, then adds the dashboard, safety, ordering, and narrow-terminal completion needed to close the issue.

User impact

Users can copy every unpriced model ID from normal terminal output and the dashboard always points to a complete runnable command, even in narrow terminals.

Preservation and out of scope

• Existing models output and its one-cent default remain unchanged without --unpriced.
• Explicit --min-cost and --top options remain authoritative.
• JSON remains lossless for automation.
• No pricing or spend is invented or changed.

Testing

• Focused model, dashboard, overview, and CLI suites: 272 passed.
• Full root suite: 2,627 passed, 5 skipped.
• Serial lock suite: 26 passed.
• Desktop suite: 468 passed.
• Root, dashboard, and desktop typechecks passed.
• CLI, dashboard, and desktop builds passed.
• Built CLI exercised with priced, unpriced, and hostile raw IDs in an isolated home.
• Real controlling-PTY dashboard checks passed at 42, 43, 44, and 80 columns with clean terminal teardown.
• Rebuilt Electron app was launched and clicked through against the isolated fixture with no real user data.

Fixes #969.