refactor(dc_measurements,dc_util): unify parameter declaration on dc_util helpers

[Minipada]

Summary

• Unifies parameter declaration across dc_measurements/dc_group onto dc_util::get_*_type_param()/get_*_param(): all 34 Measurement/Condition plugin .cpp files and measurement_server.cpp's own 5 raw declare_parameter + 3 direct nav2_util::declare_parameter_if_not_declared call sites now go through dc_util, instead of ~90 call sites split across three inconsistent patterns.
• dc_util/include/dc_util/node_utils.hpp rewritten: the 14 near-identical helper bodies collapse onto one shared detail::declare_and_get<T>() core, extended with the type coverage plugins actually needed (double, mandatory vector<bool>/vector<int64_t>/vector<double>) and a node-level (unprefixed) variant. The broken, unused get_float_type_param (declared PARAMETER_DOUBLE, returned int, zero call sites) was deleted.
• Decision recorded in docs/adr/0008-dc-util-owns-parameter-declaration.md: nav2_util stays a dependency (MeasurementServer already inherits nav2_util::LifecycleNode), dc_util becomes the single sanctioned wrapper around it, and dc_group's existing plain Python declare_parameter calls are left as-is (no equivalent idempotency problem exists there).
• Convention documented for plugin authors in doc/src/dc/contributing.md.
• Two pre-existing, unrelated bugs surfaced while cross-checking every declared-vs-read parameter name/type and were deliberately left untouched (flagged inline, not fixed, per "no behaviour change"): bool_equal.cpp's value_ field is double despite a PARAMETER_BOOL declaration; distance_traveled.cpp declares transform_tolerance but reads back the different, undeclared transform_timeout.

Closes #178

Test plan

• colcon build --packages-select dc_util dc_core dc_measurements dc_interfaces dc_common dc_group — clean, 6/6 packages, zero errors/warnings (real ROS 2 Jazzy Podman environment)
• colcon test --packages-select dc_util dc_measurements dc_group — 46 tests, 0 errors, 0 failures, 0 skipped
• pre-commit run on all changed files — clean (clang-format, black, codespell, XML/package metadata checks); only the pre-existing, environment-only poetry-requirements failure reproduces, unrelated to this diff

🤖 Generated with Claude Code

https://claude.ai/code/session_01L56mFyxLcigqQxzZ7BzNgs

[codecov]

Codecov Report

❌ Patch coverage is 36.64596% with 102 lines in your changes missing coverage. Please review.
✅ Project coverage is 40.82%. Comparing base (2b7cc67) to head (14be548).

Files with missing lines	Patch %	Lines
dc_measurements/plugins/measurements/camera.cpp	0.00%	15 Missing ⚠️
dc_util/include/dc_util/node_utils.hpp	62.86%	13 Missing ⚠️
dc_measurements/plugins/measurements/ip_camera.cpp	0.00%	10 Missing ⚠️
dc_measurements/src/measurement_server.cpp	62.50%	6 Missing ⚠️
dc_measurements/plugins/measurements/map.cpp	0.00%	5 Missing ⚠️
...easurements/plugins/conditions/double_inferior.cpp	0.00%	3 Missing ⚠️
...easurements/plugins/conditions/double_superior.cpp	0.00%	3 Missing ⚠️
...asurements/plugins/conditions/integer_inferior.cpp	0.00%	3 Missing ⚠️
...asurements/plugins/conditions/integer_superior.cpp	0.00%	3 Missing ⚠️
...easurements/plugins/conditions/list_bool_equal.cpp	0.00%	3 Missing ⚠️
... and 19 more

Additional details and impacted files

@@            Coverage Diff             @@
##            jazzy     #317      +/-   ##
==========================================
+ Coverage   40.48%   40.82%   +0.34%     
==========================================
  Files          82       82              
  Lines        5094     4920     -174     
==========================================
- Hits         2062     2008      -54     
+ Misses       3032     2912     -120     

Flag	Coverage Δ
cpp-jazzy	40.82% <36.65%> (+0.34%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.