docs: per-page scoped labels to fix cross-page :ref: resolution

[petrkalina]

Problem

When the same .. _label: is declared in multiple .rst files (e.g. dcmRulePriority lives in 7 different config pages), Sphinx picks one as the canonical target for :ref: resolution. All other pages' :ref:\title `` calls resolve to that single page.

User-visible effect: clicking Rule Priority in the Archive Attribute Coercion table jumps to studyRetentionPolicy.html#dcmrulepriority instead of staying on the current page. This affects 221 of 731 attribute labels (~30%) — worst offenders include dcmProperty (24 files), cn (20), dicomDescription (12), dcmURI (11), dicomAETitle (10).

Fix — Option B (preserves external URLs)

For every existing .. _attrName: declaration, stack a per-page-scoped twin below it:

    .. _dcmRulePriority:
    .. _archiveAttributeCoercion-dcmRulePriority:

Then rewrite intra-file :ref:\text `` calls to use the scoped form:

:ref:`Rule Priority <archiveAttributeCoercion-dcmRulePriority>`

Sphinx now resolves the :ref: per page (no more dedup ambiguity). The original .. _attrName: label stays put, so the rendered HTML emits both anchor IDs side by side — existing external links that hard-coded the old anchor (e.g. archiveAttributeCoercion.html#dcmrulepriority) keep working unchanged.

conf.py: added suppress_warnings = ['ref.label'] so the now-intentional duplicate bare labels don't spam the build log.

Stats

	Count
.rst files changed	76
Scoped labels added	1,165
:ref: references rewritten	1,135
Duplicate-label warnings before	many (was part of the ~50 warning baseline)
Duplicate-label warnings after (suppressed)	0

Verification (local Sphinx 5.0 build with sphinx_rtd_theme==1.0.0)

archiveAttributeCoercion.html rendered HTML for Rule Priority row:

<p id="archiveattributecoercion-dcmrulepriority">   <!-- new scoped anchor -->
  <span id="dcmrulepriority"></span>                <!-- old anchor preserved -->
  <a href="#archiveattributecoercion-dcmrulepriority">Rule Priority</a>
</p>

Same row on studyRetentionPolicy.html now also links to its own #studyretentionpolicy-dcmrulepriority — i.e. each page resolves locally.

External URLs that consumers may have bookmarked (archiveAttributeCoercion.html#dcmrulepriority, archiveNetworkAE.html#dcmretrieveaet, etc.) continue to work because the legacy id= attributes are still emitted on every page.

Reproducibility

The rewrite is idempotent. The script that produced the diff is included at tools/rewrite_labels.py — re-running it against docs/ is a no-op once applied.

Companion repo

The HL7 conformance statement (dcm4chee-arc-hl7cs) was checked — its labels are all unique across pages, so this fix isn't needed there.