feat: expose aibridged metrics - #20865

# HELP coder_aibridged_injected_tool_invocations_total The number of times an injected MCP tool was invoked by aibridge.
# TYPE coder_aibridged_injected_tool_invocations_total counter
coder_aibridged_injected_tool_invocations_total{model="gpt-5-nano",name="coder_list_templates",provider="openai",server="https://nlhlvn9in25q6.pit-1.try.coder.app/api/experimental/mcp/http"} 1
# HELP coder_aibridged_interceptions_duration_seconds The total duration of intercepted requests, in seconds. The majority of this time will be the upstream processing of the request. aibridge has no control ov
er upstream processing time, so it's just an illustrative metric.
# TYPE coder_aibridged_interceptions_duration_seconds histogram
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="0.5"} 0
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="2"} 0
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="5"} 3
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="15"} 6
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="30"} 6
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="60"} 6
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="120"} 6
coder_aibridged_interceptions_duration_seconds_bucket{model="gpt-5-nano",provider="openai",le="+Inf"} 6
coder_aibridged_interceptions_duration_seconds_sum{model="gpt-5-nano",provider="openai"} 34.120188692
coder_aibridged_interceptions_duration_seconds_count{model="gpt-5-nano",provider="openai"} 6
# HELP coder_aibridged_interceptions_inflight The number of intercepted requests which are being processed.
# TYPE coder_aibridged_interceptions_inflight gauge
coder_aibridged_interceptions_inflight{model="gpt-5-nano",provider="openai",route="/v1/chat/completions"} 0
# HELP coder_aibridged_interceptions_total The count of intercepted requests.
# TYPE coder_aibridged_interceptions_total counter
coder_aibridged_interceptions_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",method="POST",model="gpt-5-nano",provider="openai",route="/v1/chat/completions",status="completed"} 6
# HELP coder_aibridged_non_injected_tool_selections_total The number of times an AI model selected a tool to be invoked by the client.
# TYPE coder_aibridged_non_injected_tool_selections_total counter
coder_aibridged_non_injected_tool_selections_total{model="gpt-5-nano",name="read_file",provider="openai"} 2
# HELP coder_aibridged_prompts_total The number of prompts issued by users (initiators).
# TYPE coder_aibridged_prompts_total counter
coder_aibridged_prompts_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai"} 4
# HELP coder_aibridged_tokens_total The number of tokens used by intercepted requests.
# TYPE coder_aibridged_tokens_total counter
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="completion_accepted_prediction"} 0
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="completion_audio"} 0
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="completion_reasoning"} 1664
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="completion_rejected_prediction"} 0
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="input"} 13823
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="output"} 2014
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="prompt_audio"} 0
coder_aibridged_tokens_total{initiator_id="95f6752b-08cc-4cf1-97f7-c2165e3519c5",model="gpt-5-nano",provider="openai",type="prompt_cached"} 31872