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

@@ -0,0 +1,16 @@
+# 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.