Handle missing satellite objects and extend BDS satellite identifiers

[JianquanLu]

Summary

• extend the static BDS satellite identifier list from C01-C46/C59-C60 through C01-C63
• guard against a missing satellite object before accessing its antenna calibration
• warn and skip an observation safely if an unknown satellite identifier is encountered

Problem

The static BDS satellite list omits C47-C58 and C61-C63. When an observation contains one of these satellites, such as C56, t_gallobj::obj() returns an empty shared_ptr even when the ANTEX file contains a calibration record for that satellite.

great::t_gpvtflt::_preprocess() then dereferences it unconditionally:

shared_ptr<t_gobj> sat_obj = this->_gallobj->obj(satname);
shared_ptr<t_gpcv> sat_pcv = sat_obj->pcv(_epoch);

This causes a segmentation fault/access violation at the first epoch containing C56.

Fix

1. Add C47-C58 and C61-C63 to the BDS satellite identifier list, allowing valid current BDS satellites to be initialized normally.
2. Retain a null check in _preprocess() so a future unknown or unavailable satellite object produces a warning and is removed from that epoch instead of crashing the process.

Verification

Tested from commit 3b4f383a2724c1b0c4748cb0b0cb80e0bc430740 using an ANTEX file containing a C56 record:

• before the fix, processing stops with a segmentation fault when C56 first appears
• after the fix, C56 is resolved as a normal satellite object rather than skipped
• all nine previously failing observation datasets pass their original trigger epochs and complete with exit 0
• two delayed failures were reproduced at the exact epochs where C56 first appeared and both complete after the fix
• a good-environment static observation regression also completes successfully
• MSVC Release build and git diff --check pass

No observation data, generated products, binaries, or local paths are included in this PR.

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