feat: first-class callsign, display name, and export name composition

[pskillen]

Problem

Channels today store a single name (OpenGD77 Channel Name) and a derived callsign (first whitespace-separated token of name). That works for import but does not model the operator's intent:

• Callsign — e.g. GB7GL (repeater/site id, used for map labels and external lookups)
• Display name — e.g. Glasgow (human-readable qualifier)

On export to CPS CSV, operators often want a composed wire name such as GB7GL Glasgow, with control over whether/how the callsign is included. This was scoped in #11 and deferred from PR #42; see docs/features/crud/crud-outstanding.md.

Intended outcome

Data model

• Treat callsign and name (display name) as first-class, independently editable channel fields.
• Add a per-channel export name mode (working title — refine in UI copy), e.g.:
  • verbatim — export display name only (Glasgow)
  • callsign — GB7GL Glasgow (full callsign + space + display name)
  • callsign_suffix — last two letters + display name (GL Glasgow) — common convention
  • omit_callsign — same as verbatim; alias if clearer in UI
• Compose the OpenGD77 Channel Name on export from callsign + display name according to the selected mode.
• Respect CPS field length limits when composing (truncate or validate with a clear error — decide during implementation).
• Bump schema version and document migration (existing codeplugs: keep name as display name, infer callsign best-effort from current name / callsign).
• While we're here, add a description field (single line) and note (multi line). These will generally be internal to our models but some CPS may support

Import (best effort)

• On OpenGD77 CSV import, parse Channel Name with a standard callsign regex (UK repeater / amateur allocation patterns).
• When a callsign prefix is recognised, split into callsign + display name (name).
• Default export name mode to callsign + display name when a split was inferred; otherwise verbatim.
• Round-trip: import GB7GL Glasgow → edit display name → export → CPS still gets a valid composed name.

Current helper: extractCallsign() in src/lib/csv.ts (first token only) — replace/extend for regex-based split.

Export

• OpenGD77 Channels.csv Channel Name column is composed from internal fields + export mode (not a blind copy of name).
• Zone Channel1…Channel80 wire names must use the same composition rules so FK integrity holds.

UI

• Channel create/edit: separate inputs for callsign and display name. add notes and description fields
• Export name mode control must make the feature obvious but optional — users who want CPS names verbatim set mode accordingly.
• Show a live preview of the exported wire name as fields/mode change.
• Channel detail/list: show both fields; band pills etc. unchanged. add col for description, hideable, default on.

Map

• CodeplugMap and related helpers currently infer callsign from name (markerLabel, fullChannelName toggle in src/lib/channels.ts).
• After this change, use channel.callsign directly (no inference from display name).
• Document map label behaviour in docs/features/map/.

Documentation (deliver with implementation)

Area	Path
Display / naming conventions	docs/reference/display-conventions.md
Data model	docs/features/data-model/README.md + src/models/codeplug.ts
Import split logic	docs/features/import/opengd77.md (and/or docs/features/import/)
Export composition	docs/features/export/README.md + OpenGD77 export module docs
CRUD / progress	docs/features/crud/crud-outstanding.md, crud-progress.md

Acceptance criteria

• callsign and name (display name) are editable independently in channel CRUD
• Per-channel export name mode with at least: verbatim, full callsign prefix, last-two-letters prefix
• Export composes Channel Name and zone member names consistently; respects length limits
• Import best-effort splits recognised callsign prefixes; sets sensible default export mode
• Map markers and external links use channel.callsign, not derived-from-name
• Schema migration for existing localStorage projects
• Tests for split/compose round-trip and edge cases (no callsign, display name only, long names)
• Docs updated as listed above

Related

• Parent context: #11 (CRUD channels — export prefix bullet)
• Shipped without this: PR #42
• Data model today: docs/features/data-model/README.md (callsign noted as derived)

[pskillen]

Tracked under epic #93 (pristine vendor-neutral internal data model). This is Phase 5 of that epic.