Make the merged repository coherent: README, state, and internal links

The mechanical merge preserved both histories but left two repositories
sitting side by side rather than one repository. This is the part that
makes it whole.

A top-level README explains the three strands - the telescope network
and campaign, the processing code, and in-person observing plans - and
says plainly that image data does not live here, because that is the
first question anyone will have when they find a pipeline with no
pixels.

state/PROJECT.md was still describing a markdown-only reference project
whose scope explicitly EXCLUDED automating bookings and image
processing. Both of those are now most of what the project does, so the
objective, scope and key facts are rewritten to match reality.

state/DECISIONS.md records why the merge happened - the two repos were
split by chronology rather than design, and the seam was already
leaking, with the campaign's TODO citing results held in the other repo
and the pipeline's README explaining a campaign it did not contain. It
also records that the image data deliberately stays out of the
repository.

state/TODO.md gains the pipeline and observing work that previously had
nowhere to live, including the measurement that changes the pipeline
plan: per-frame processing is 2.9 seconds and the whole 24-frame session
is 1.1 minutes single-threaded, so a scheduler earns nothing on stacking
and should be pointed at the Monte Carlo stages instead.

Internal links fixed for the new paths: pipeline/README.md referred to
session-scripts/ throughout, and itelescope/README.md pointed at a
state/ directory that is now one level up.

The .gitignore conflict between the two repositories is resolved by
combining them, with image formats ignored globally except under docs/,
where documentation figures are committed deliberately.

state/PROJECT.md

@@ -1,29 +1,41 @@
-# Project: itelescope
+# Project: astrophotography
 
 > The anchor document. A session that reads only this, TODO.md and DECISIONS.md should
 > understand what the project is and what to do next. Keep it current.
 
 ## Objective
 
-A reference and review of the iTelescope.net remote telescope network: what each
-telescope is, what it is good at, and which one to book for a given kind of target.
+Take astronomical images, process them properly, and understand what is in them.
+Three strands, all in this repository since the 2026-07-21 merge of the
+`itelescope` and `astro-pipeline` repositories:
 
-Since 2026-07-18 the active objective is the drain campaign (CAMPAIGN.md): spend
-the account's 2,638 points on southern-sky imaging by 10 Aug 2026, download all
-data, then cancel the membership before the 12 Aug renewal. Cancellation needs
-explicit user confirmation on the day.
+1. **Remote imaging** (`itelescope/`) - a review of the iTelescope.net network
+   and which scope to book for a given target. The active objective is the drain
+   campaign (`itelescope/CAMPAIGN.md`): spend the account's remaining points on
+   southern-sky imaging by 10 Aug 2026, download all data, then cancel before the
+   12 Aug renewal. **Cancellation needs explicit user confirmation on the day.**
+2. **Processing and analysis** (`pipeline/`) - the code that turns frames into
+   calibrated, plate-solved images and into measurements. Proven on the NGC 5128
+   session of 2026-07-21; being productionised into a staged, containerised
+   pipeline that can run under a scheduler.
+3. **Observing in person** (`observing/`) - currently the total solar eclipse of
+   12 Aug 2026, seen from Menorca.
 
 ## Scope
 
-- In scope: reviews and spec tables for every telescope on the iTelescope network,
-  grouped by observatory; source data snapshots; guidance on choosing a scope.
-- Out of scope: automating bookings, image processing, anything requiring the
-  iTelescope login (the launchpad at go.itelescope.net is authenticated).
+- In scope: the telescope network reference; booking and running remote sessions;
+  calibration, stacking, plate solving, rendering and analysis code; observing
+  plans for trips.
+- Out of scope: the image data itself. Sessions stay on disk and are located
+  through `ASTRO_SESSION`; a single frame is 61 MB and a session is several GB.
+  Each session directory carries its own METHODS.md.
+- Previously out of scope, now central: automating bookings and image
+  processing. Both proved necessary and both are done.
 
 ## Audience
 
-Laurence, when planning imaging or photometry runs on iTelescope, and anyone else
-choosing a telescope on the network.
+Laurence, when planning or processing imaging runs, and anyone else choosing a
+telescope on the network or wanting to reproduce a result.
 
 ## Description
 
@@ -42,6 +54,12 @@ assessments plus a "which scope for what" guide.
 ## Key facts
 
 - Trunk branch: main
-- Forge / remote: https://git.discworld.casa/laurence/itelescope
-- Runtime / stack: markdown only; source data in data/ as CSV
-- How to run it: nothing to run; read TELESCOPES.md
+- Forge / remote: https://git.discworld.casa/laurence/astrophotography
+  (merged 2026-07-21 from `itelescope` + `astro-pipeline`; both histories intact)
+- Runtime / stack: markdown for the reference and campaign; Python 3.12 for the
+  pipeline (numpy, scipy, astropy, scikit-image, sep, astroalign, photutils,
+  astroquery, matplotlib)
+- How to run it: read `itelescope/TELESCOPES.md` to choose a scope; set
+  `ASTRO_SESSION` and run `pipeline/*.py` to process a session
+- Image data is NOT in this repo: it lives on disk per session, each with its
+  own METHODS.md