WIP: simplify loop closure evaluation by image index

[dvorak0]

Summary\n- open a clean draft PR on UniflexAI/tinynav\n- implement simplified loop-closure evaluation in a fresh worktree\n- keep the evaluation aligned by image index instead of timestamp interpolation\n\n## Planned work\n- build Map A from bag A\n- sample bag B by image index\n- localize sampled images in Map A\n- get reference poses from map B by image index\n- report loop-closure metrics without timestamp interpolation\n\n## Status\nDraft PR only for now; implementation and benchmark runs are next.\n

[github-actions]

cloc	github.com/AlDanial/cloc v 2.04 T=0.12 s (305.3 files/s, 46378.5 lines/s)

Language	files	blank	comment	code
Python	12	542	244	3004
C++	4	60	38	409
Markdown	4	143	6	405
Bourne Shell	10	17	7	163
Dockerfile	1	27	23	159
JSON	2	8	0	57
TOML	1	5	0	52
make	1	18	12	49
CMake	1	4	0	17
--------	--------	--------	--------	--------
SUM:	36	824	330	4315

[github-actions]

cloc	github.com/AlDanial/cloc v 2.04 T=0.12 s (311.8 files/s, 47364.9 lines/s)

Language	files	blank	comment	code
Python	12	542	244	3004
C++	4	60	38	409
Markdown	4	143	6	405
Bourne Shell	10	17	7	163
Dockerfile	1	27	23	159
JSON	2	8	0	57
TOML	1	5	0	52
make	1	18	12	49
CMake	1	4	0	17
--------	--------	--------	--------	--------
SUM:	36	824	330	4315