Guard schematic TextColor access without stopping Altium polling

[TerrenceHenry]

Querying TextColor on a schematic power object raised an Undeclared identifier: TextColor modal on Altium 21.4.1.30 and stopped polling. The getter, setter, filters and creation paths could reach the same unsupported member.

Allow TextColor only on the documented port, sheet-entry and harness-entry interfaces, and access it through typed locals. Unsupported query fields remain empty with unreadable diagnostics; project queries now include those diagnostics too. Filters refuse known unsupported properties before comparison, so TextColor= cannot match an unreadable value. Modification preflights the complete assignment list before moving or recolouring an object; creation uses the existing single refusal and indexed batch-failure format. Independent valid batch items continue.

The assignment preflight also protects the already-guarded Text/IsHidden pairs. It does not make arbitrary writes transactional or claim a complete property capability map. Script version is bumped to 2026.10.03.1; reload the script project or restart Altium before acceptance.

Closes #37.

Validation:

• DelphiScript lint: 11 files, zero errors or warnings; script bundle build passed.
• Focused property/lint suite: 53 passed, 3 skipped for unavailable local Free Pascal. Source-mutation tests detect removed read/write guards, admitting power objects, direct generic-member access and removed preflight checks.
• Upstream CI passed: the main suite reports 5,631 passed, 104 skipped and 1 xfailed; the Free Pascal 3.2.2 job reports 70 passed with no skips, including production guard/filter and creation tests. CI run.
• Full offline suite: 5,408 passed, 147 skipped, 1 xfailed, 6 initial failures. Five were nested pytest temporary-directory access failures; one exposed a stale release-document version expectation. After directing nested processes to a writable scratch directory and updating the expectation, all 11 tests in the affected files passed. Final version/property checks: 34 passed, 3 compiler-dependent skips.
• Live acceptance passed on Altium 21.4.1.30 with running script 2026.10.03.1 on 2026-10-03, using a disposable schematic and explicit scratch-project scope. Power-object and net-label TextColor queries returned empty fields plus unreadable diagnostics without a modal or polling stop; project-scope diagnostics also passed. Empty and numeric unsupported filters matched zero objects; delete with TextColor= left the power object intact. Single and batch mixed writes rejected TextColor and preserved Color and position; a valid independent batch write applied. Single invalid creation was refused; mixed creation produced exactly two valid objects and indexed failures for items 0 and 2. Port and sheet-entry TextColor values read back as 16711680 after save, close and reopen, including supported-property filters. Ping continued after rejected operations. Scratch documents/project were closed; original editor restored; 32 original documents remained with no unsaved documents. Polling was stopped afterwards through the dashboard.

Limits and related observation: harness-entry round trips were not performed because the generic object-type mapping does not expose that owner and no fixture was available; its owner guard is covered by the compiler job. Existing batch-modify diagnostics are cumulative: a later valid item inherits a failure note although its write readback passes. This reporting issue is outside the TextColor crash fix. Upstream CI and the live acceptance cases above are complete.

[salitronic]

Thanks Terrence, merged as 4c2e274 with your authorship. I resolved the conflicts with the latest main and bumped the script to 2026.10.05.1.