Telescope review: all 23 active iTelescope systems

Adds TELESCOPES.md, a per-observatory review of every telescope on the
iTelescope.net network with a spec block and an assessment for each, a
'choosing a telescope' use-case table, and general observations (CCD to CMOS
migration, Bin2 software limits, elevation limits, network-side calibration).

Data sourcing:
- data/itelescope-telescopes.csv is a verbatim CSV export of iTelescope's
  maintained specs Google Sheet (24 rows: 23 active scopes + T74 placeholder).
- The support article (Freshdesk 247371) supplied observatory groupings and
  minimum elevation limits; it still lists T9/T19/T31/T69 which the sheet has
  dropped - the review follows the sheet and records the discrepancy.
- go.itelescope.net is an authenticated app shell; nothing was scraped from it.

Also fills in the remaining state/ files: TODO (pending: T74 specs, retired
scope reconciliation, periodic sheet refresh), DECISIONS (source-of-truth
choice, single-document structure, no launchpad scraping), NOTES (refresh
command, CSV quirks), ARCHITECTURE (repo layout), and README.

state/ARCHITECTURE.md

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+# Architecture
+
+> How the system is built and why. Update this when the structure changes; a change is
+> not finished until this reflects it.
+
+A documentation-only repo; there is no code.
+
+- `TELESCOPES.md`: the deliverable. Per-observatory sections, one entry per telescope
+  (spec bullets then a review paragraph), a "choosing a telescope" table, and general
+  observations. Compiled from the sources below, dated in its header.
+- `data/itelescope-telescopes.csv`: verbatim CSV export of iTelescope's maintained
+  specs Google Sheet. Treated as the source of truth for numbers; re-exported to
+  refresh (see state/NOTES.md).
+- `state/`: Default Workflow project memory.
+- `CLAUDE.md` + `docs/`: the Default Workflow itself, copied from the
+  Default-Workflow repo so the project is self-contained.

state/DECISIONS.md

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+# Decisions
+
+> A dated, append only log of decisions and their rationale. Newest at the top. Never
+> rewrite past entries; if a decision is reversed, add a new entry that says so.
+
+## 2026-07-17: follow the Google Sheet, not the support article
+
+The support article (https://support.itelescope.net/support/solutions/articles/247371)
+and the maintained Google Sheet
+(https://docs.google.com/spreadsheets/d/1jZWkkjewOuyNC9YzQ8y2d0pO1e4T7EBeysmQMPBVSOk/)
+disagree: the article lists T9, T19, T31, T69, which the sheet omits; the sheet has
+T25, T26, T59, T71-T75, T80, which the article lacks. The article itself points to
+the sheet as the current source, so the review follows the sheet and notes the
+discrepancy. The sheet CSV export is snapshotted in data/ so the review's numbers
+remain reproducible even if the sheet changes.
+
+## 2026-07-17: single review document, not per-telescope files
+
+23 active scopes each need only a spec block and a short assessment; one TELESCOPES.md
+grouped by observatory reads better and is easier to keep current than 23 stub files.
+Revisit if per-scope content grows (photos, session logs).
+
+## 2026-07-17: no launchpad scraping
+
+https://go.itelescope.net/ is an authenticated app shell with no public data. All
+content comes from public support pages and the public sheet; nothing in this repo
+requires iTelescope credentials.
+
+Per-telescope detail pages, if ever needed:
+support.itelescope.net/support/solutions/articles/231901-231920 (older scopes),
+245471 (T68), 251171 (T70), 251556 (T69), 251589 (T19).

state/NOTES.md

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+# Notes
+
+> Working notes, gotchas, environment quirks, and dead ends to avoid. Free form. The
+> point is to save a future session from rediscovering something the hard way.
+
+- Refresh the specs snapshot with:
+  `curl -sL "https://docs.google.com/spreadsheets/d/1jZWkkjewOuyNC9YzQ8y2d0pO1e4T7EBeysmQMPBVSOk/export?format=csv" -o data/itelescope-telescopes.csv`
+- The CSV has multi-line cells (quoted); line count is not row count. Telescope rows
+  start `T<number>,`; observatory header rows have an empty first column.
+- Sensors are 16-bit ADC unless noted (T20's ASI2400C is 14-bit).
+- Free scopes (30 min/day): T68 (Utah), T33 (Siding Spring).
+- Minimum elevation limits come from the support article, not the sheet.

state/PR_TEMPLATE.md

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+# <feature title>
+
+> Fill this in when opening the PR. It is the summary a later documentation session
+> reads to write the docs, so make it complete and self contained.
+
+## Feature
+
+<What was built, in plain terms.>
+
+## What was achieved
+
+<The outcome. What now works that did not before.>
+
+## How to verify
+
+<Steps or commands to confirm it works.>
+
+## Tools used
+
+<Languages, libraries, commands, services involved.>
+
+## How it works
+
+<Enough detail for a documentation session to start from this PR alone: the approach,
+the key files, and how the pieces connect.>
+
+## State updated
+
+- [ ] `state/TODO.md`
+- [ ] `state/DECISIONS.md` (if a decision was made)
+- [ ] `state/ARCHITECTURE.md` (if the structure changed)
+
+## Follow ups
+
+<Anything deferred or worth doing next.>

state/TODO.md

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+# TODO
+
+> The current state of play. Keep it honest and current; this is what the next session
+> reads to know what to do. Move items between sections as they progress.
+
+## Done
+
+- 2026-07-17: repo created on git.discworld.casa, Default Workflow scaffold copied in.
+- 2026-07-17: specs sheet snapshotted to data/itelescope-telescopes.csv (24 scopes).
+- 2026-07-17: TELESCOPES.md written: per-scope reviews for all 23 active telescopes
+  plus a choosing guide (T74 noted as in commissioning, no specs published).
+
+## In progress
+
+- (nothing)
+
+## Pending
+
+- Fill in T74 when iTelescope publishes its specs.
+- Reconcile the retired scopes (T9, T19, T31, T69): the support article still lists
+  them but the maintained sheet does not; confirm status and note it.
+- Optional: per-telescope detail pages on support.itelescope.net (links in
+  DECISIONS.md) hold photos and operational history if deeper entries are ever wanted.
+- Periodic refresh: re-export the Google Sheet and diff against data/ to catch new or
+  changed systems.