For specific LRU contexts (version, param, param_value), the Bicep LS was
appending its own random/irrelevant completions alongside the LRU catalog
items. The LS has no knowledge of the private ACR registry, so its suggestions
in these positions are noise.
Now the LS items are discarded entirely for these three contexts. LS items
are still kept (below LRU items) for module_path and unknown contexts.
Two bugs fixed in BicepModuleCatalog:
1. as_completion_items() generated 'br/modules:bicep/modules/appservice:...'
but bicepconfig modulePath='bicep' means Bicep prepends 'bicep/' automatically.
Fix: store ref_path = path.removeprefix('bicep/') and use it in insertText.
Correct output: 'br/modules:modules/appservice:2.3.x'
2. version/param lookups used get_module_by_name() which only matches the last
path segment ('appservice'). New-style refs capture 'modules/appservice' from
the regex, so lookup returned empty. Fix: add get_module_by_ref() that matches
both ref_path and bare name.
Also fixes _iac_param_map to strip path prefix so IAC source descriptions
still enrich completions for 'modules/appservice' refs.
All 63 tests pass.
